1. Field
The present disclosure relates generally to switched mode power converters and, more specifically, the present disclosure relates to switched mode power converters utilizing current mode control.
2. Related Art
Electronic devices use power to operate. Switched mode power converters are commonly used due to their high efficiency, small size, and low weight to power many of today's electronics. Conventional wall sockets provide a high voltage alternating current (ac) power. In a switched mode power converter, a high voltage ac input is converted to provide a regulated direct current (dc) output through an energy transfer element. In operation, a switch is utilized to provide the desired output by varying the duty ratio (typically the ratio of the on-time of the switch to the total switching period), varying the switching frequency, or varying the number of pulses per unit time of the switch in a power converter.
The switched mode power converter also includes a controller that typically provides output regulation by sensing and controlling the output in a closed loop. The controller may receive a feedback signal representative of the output and the vary one or more parameters (such as duty ratio, switching frequency, or the number of pulses per unit time of the switch) in response to the feedback signal to regulate the output to a desired quantity. Various modes of control may be utilized. One mode of control is known as pulse width modulation (PWM) peak current mode control. In PWM peak current mode control, the switch remains on until the current in the switch reaches a current limit. Once the current limit is reached, the controller turns the switch off for the remainder of the switching period. In general, a higher current limit results in a longer on-time of the switch and a larger duty ratio.